Indeed, my 15/60 NST pulls over 20 Amps from the wall WITH PFC caps.
Having the PFC caps is the difference between tripping and not tripping the
breaker. And while I've never attempted to measure it, I believe that the
line voltage applied to the NST primary is greater with the caps by virtue
of lower IR losses in the mains wiring. More volts is more power to the
sparks!
Regards, Gary Lau
MA, USA
On Sat, Dec 3, 2016 at 11:59 PM, jimlux <jimlux@xxxxxxxxxxxxx> wrote:
> On 12/3/16 7:33 PM, Chris Boden wrote:
>
>> I understand that, but....with an NST powered coil, it's rather moot isn't
>> it?
>>
>
> You're drawing more current through your variac, which will get hotter.
> And while a single 30mA 15 kV NST is only going to be 400-500 VA, if you
> start ganging them up in parallel, or getting a 60mA 15 kV unit, then
> you're getting up towards where the current draw is an issue
>
>
>
>
>> I mean, you're drawing only a few hundred watts. The "wasted power" isn't
>> enough to trip the breaker, and the impact in your electric bill is on par
>> with your doorbell.
>>
>
> The bill will be the same whether you have PFC or not - your meter only
> measures active power, not reactive power. So if you were drawing, say, 15
> A @ 120V (1800VA) and the PF were 50%, your meter is only going to spin for
> a 900W load.
>
> (there's a very small effect from the IR losses in the wiring because of
> the reactive power, but it's "small".. IR loss is <2% with 100% PF, and
> only slightly more (<4%) with 50% PF
>
>
>
>
>> Maybe I'm missing something, my electric bills are a little different than
>> most. It just seems like a lot of effort for very little tangible gains.
>>
>> We certainly don't worry about it here in the lab.
>>
>
> I sort of agree - there's not a lot to be gained by worrying about PF.
>
>
>
>
>
>
>
>> On Sat, Dec 3, 2016 at 7:58 PM, jimlux <jimlux@xxxxxxxxxxxxx> wrote:
>>
>> On 12/3/16 4:03 PM, Chris Boden wrote:
>>>
>>> The question I have is......Why? Why would you want to lower the PF?
>>>>
>>>>
>>>>
>>>> Total line current is less - the meter spins slowly for the current, but
>>> the breaker will trip.
>>>
>>> if you have 71% PF, you'll draw 14 amps from the socket, but only be
>>> really using 10 of it to make sparks.
>>>
>>>
>>>
>>>
>>>
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>>>
>>>
>>
>>
>>
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